Question: Who was the head of the Lisbon government beginning in April 2015?
Paraphrase: Who became the head of the Lisbon government in April 2015?
SPARQL (Wikidata): SELECT ?obj WHERE { wd:Q597 p:P6 ?s . ?s ps:P6 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'2015')) }